J. Arnau et al., HETEROLOGOUS GENE-EXPRESSION OF BOVINE PLASMIN IN LACTOCOCCUS-LACTIS, Applied microbiology and biotechnology, 48(3), 1997, pp. 331-338
Heterologous production of bovine plasmin was studied in the industria
lly relevant bacterium Lactococcus lactis. Two sets of lactococcal gen
e expression signals were coupled to the region of the plasmin gene co
ding for the serine protease domain. When the promoter region of the p
rtP gene was used, plasmin was detected mainly intracellularly in stra
in BPL25 by Western blot hybridization. The intracellular presence of
plasmin led to physiological stress. Expression of the plasmin gene dr
iven by the promoter and complete signal sequence of the lactococcal u
sp45 gene resulted in efficient plasmin secretion in strain BPL420. Ce
ll lysis was observed in strains producing plasmin fragments including
the catalytic domain, but not in control strains, which only produced
a non-catalytic region of plasmin. The plasmin produced was shown to
be biologically active.